This proposal investigates the use of a novel, passive personal monitoring system to stem the tide in the epidemic of deaths due to unintentional opioid drug overdoses. In the U.S. in 2013, opioid drug overdoses (including prescription pain relievers and heroin) caused 24,000 deaths, a number that has increased dramatically over the past two decades. A person who overdoses on an opioid drug can have their breathing slow and then stop during sleep, leading to anorexic brain damage or death. We propose PlusOne, a noncontact wholehome breathing monitor that is always on and provides early detection of severe respiratory depression and sends an alert in time for intervention to prevent death. The overall goal of this project is to develop a beta prototype and to validate the technology in human subject studies. This validation will provide the foundation for early commercialization of a consumer respiratory monitor and provide the background for future clinical trials, performed in Phase II, in order to request FDA regulatory approval for a clinical device. Currently, atrisk patients who live or sleep alone are at high risk for overdose death because periodic visits or monitoring is insufficient to detect an overdose soon enough to prevent death. No other noncontact breathing sensor or wearable sensor provides robust protection, as people don't plan an overdose and thus don't plan to wear or position themselves to be monitored after an overdose. PlusOne has been tested with bench studies and preliminary human subject studies. The device has shown that it is accurate to within 0.5 bpm compared to a current clinical standard, capnograph, and that it can monitor breathing across an entire home. The steps outlined in this Phase I proposal will validate the feasibility of the technology, through (1) successful development and implementation of realtime processing algorithms, (2) a human subject study performed on sleeping individuals with sleep conditions (i.e. obstructive sleep apnea, restless leg syndrome, etc.), and (3) monthlong deployments in the homes of healthy subjects. Successful completion of these aims will provide verification and validation of the robustness of the solution we propose as well as the commercial viability for deployment in the homes of atrisk individuals. By initially targeting the market of patients in (or recently in) rehabilitation treatment, we believe PlusOne can achieve a $600 million annual revenue and decrease unintentional opioid drug overdose deaths by more than 20%.